The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant fennel in Decorah can be figured out by looking at the USDA zone info.

Planting Calendar for Fennel

Frost tolerance for fennel:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since fennel are very cold tolerant you can plant them quite a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant fennel in Decorah is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant fennel and expect a good harvest is probably August. Any later than that and your fennel may not have a chance to really do well. Starting your fennel indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Decorah. In the coldest months of winter you should expect an average low temperature of -25°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Decorah and it changes from year to year. Half of the time in Decorah last frost occurs after May 15 so be sure to be ready to protect your fennel in the event of a late frost.

USDA Zone Info for Decorah

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Decorah

You may be interested in your other planting guides for Decorah.